V-Care project

Since man has been exploring space, one of the greatest challenges has been to be able to stay there for a long period of time (6 months). It is known that with time, the absence of gravity causes a premature aging of the bones as well as a muscular atrophy in the astronaut. It is therefore essential to regularly practice optimized resistive physical exercises to counteract muscle and bone loss during space flights.

Objectives

• Detection of an individual’s joint centers to estimate joint angle oscillations during physical exercises
• Optimization of muscular fatigue with an adapted program to strengthen the muscles
• Improvement of space travel conditions and optimization of the payload at the start of the space trip

One of the objectives of the researchers is to control the posture of the astronaut during resistive exercise sessions to optimize the efficiency while reducing the risk of injury following misuse, in particular for body movements requiring high loads as it is the case with the ARED device (for “Advanced Resistive Exercise Device”) on board the International Space Station ISS. To do this, one solution is to use a tool that allows real-time tracking of movements in order to correct them in real time, as all sports coaches do.

Within the framework of a technological demonstrator, ESA asks for an evaluation of the performances of a system developed by COMEX with the support in space medicine brought by the MEDES.

Context

COMEX has developed a motion analysis system called V-Care allowing the tracking of 3D motion, the advantage of which is that it is markerless body-tracking. The system uses two cameras that are compact and easy to install.

The purpose of the study presented here was to evaluate the accuracy of this system from selected joint angles. The data obtained with V-Care was compared to a Gold Standard system in the field.

The two systems were compared during three resistive physical exercises representative of a functional evaluation at the Technosport of Aix-Marseille University.

Results

This study aimed to compare the performance of a markerless motion capture system, V-Care, to the gold standard in the field.

The V-Care system performs better in tracking the two main joints of the lower limbs. For the upper limbs, the error is more important.

In spite of this lower precision on the upper limbs, the V-Care system seems to be adapted for the real follow-up of physical exercises in the framework of space flights. Its “Plug & Play” aspect allows an easy and fast use compared to the preparation time of the standard Gold system in the field. The latter can be of the order of a day for the initial installation of a dozen cameras, plus half an hour for the installation of the markers.

Perspectives

To conclude this study, the V-Care appears to be a simple to use and sufficiently accurate tool for tracking movement during functional tasks.

The next step is to integrate the V-Care system in a resistive exercise device simulating the ARED.